بسم هللا الرحمن الرحيم

Dr Ahmed Esawy

Dr. Ahmed Eisawy

MBBS M.Sc MD

Dr Ahmed Esawy

FULL STORY OF

THYRIOD IMAGING (US.CT.MRI.NUCLEAR)

GIOTRE HYPERTHYRIODISM

(HYPERTHYROXINEMIA) HYPOTHYRIODISM

Dr Ahmed Esawy

CONTENTS 1-Normal thyriod gland imaging 2-pathology 3-differential diagnosis 4-developmental thyriod gland disease 5-diffuse thyriod gland disease (hyperthyriodism/hypothyriodism) 6-benign mass /nodule 7-malignant mass /nodule 8-TIRAD 9-nuclear thyriod gland imaging

Dr Ahmed Esawy

1-Normal thyriod gland imaging

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THE THYROID GLAND

OVER TRACHEA

TWO LARGE LATERAL LOBES CONNECTED BY AN

ISTHMUS

15 to 20 g

FUNCTIONAL UNIT IS THE FOLLICLE: EPITHELIAL

CELLS AROUND A HOLLOW VESSICLE FILLED WITH

THYROGLOBULIN

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Transverse US scan of normal thyroid/neck

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SONOGRAPHICALLY DIVIDED INTO THREE SEGMENTS UPPER ,MIDDLE ,LOWER THIRDS

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NORMAL THYROID GLAND THE NORMAL THYROID HAS THIS “GROUND GLASS” APPEARANCE. IT IS

BORDERED ANTERIORLY BY THE STRAP MUSCLES (SM), LATERALLY BY THE

CAROTID ARTERY (C), INTERNAL JUGULAR VEIN (J), AND STERNOCLEIDOMASTOID

MUSCLE (SCM). THE LONGUS COLI MUSCLE (LC) LIES POSTERIORLY. THE

ESOPHAGUS (E) PROTRUDES ON THE LEFT.

RIGHT LEFT

SM SM

SCM

SCM

TRACHEA

E LC

LC

C

C

J

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Normal Anatomy

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Normal Anatomy

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Normal Thyroid

Adult Thyroid

40-60 mm long

13-18 mm AP

Isthmus 4-6 mm AP

Newborn: 18-20

mm long; 8-9 mm

AP

Age 1: 25 mm

long; 12-15 mm AP

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Longitudinal US scan of normal thyroid/neck

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Normal thyroid gland: US

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Normal echo-pattern

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Normal thyroid gland : US

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Normal thyroid gland and thyroid mass. A, Enhanced axial neck CT at the level of the thyroid gland. Note the normal right and left lobes of the thyroid gland (L) and the isthmus (arrows).

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Normal thyroid gland. Unenhanced CT images through the upper portion (A), midportion (B), and lower portion (C) of the thyroid gland demonstrate the two lobes of the gland (black arrowheads) as structures of relatively high attenuation value adjacent to the trachea (T). The thyroid isthmus (white arrowhead) connects the right and left lobes. C, common carotid artery; J, internal jugular vein; E, esophagus; arrows, longus colli muscles.

Dr Ahmed Esawy

Normal thyroid gland. Unenhanced CT images through the upper portion (A), midportion (B), and lower portion (C) of the thyroid gland demonstrate the two lobes of the gland (black arrowheads) as structures of relatively high attenuation value adjacent to the trachea (T). The thyroid isthmus (white arrowhead) connects the right and left lobes. C, common carotid artery; J, internal jugular vein; E, esophagus; arrows, longus colli muscles.

Dr Ahmed Esawy

Normal thyroid gland. Unenhanced CT images through the upper portion (A), midportion (B), and lower portion (C) of the thyroid gland demonstrate the two lobes of the gland (black arrowheads) as structures of relatively high attenuation value adjacent to the trachea (T). The thyroid isthmus (white arrowhead) connects the right and left lobes. C, common carotid artery; J, internal jugular vein; E, esophagus; arrows, longus colli muscles.

Dr Ahmed Esawy

non-enhanced CT demonstrating slightly hyperdense thyroid gland compared to muscle tissue

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contrast enhanced CT demonstrating enhancement of thyroid tissue compared to muscle.

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T1w TSE image showing slight hyperintensity of thyroid gland compared to muscle tissue.

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T2w TSE image showing hyperintensity of thyroid gland compared to muscle tissue.

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Axial MR images of the neck. A, T1-weighted image shows mild hyperintensity in the thyroid gland. B, T2-weighted image shows a more pronounced hyperintensity, compared with muscle, in the thyroid gland.

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2-pathology

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Abnormalities of thyriod

functional Structural anatomical

Enlarged =goitre NOT ENLARGED FOCAL(mass / nodule)

hyperthyriodism hypothyriodism

euthyriod

NODULAR DIFFUSE Dr Ahmed Esawy

GOITRE =thyroid enlargment

(British English) or goiter (American English) (from the Latin gutteria, struma) is a swelling of the neck or larynx resulting from enlargement of the thyroid gland (thyromegaly), associated with a thyroid gland that is not functioning properly. Worldwide, over 90% cases of goitre are caused by iodine deficiency Goitrogens are substances (whether in drugs, chemicals, or foods) that disrupt the production of thyroid hormones by interfering with iodine uptake in the thyroid gland. This triggers the pituitary to release TSH, which then promotes the growth of thyroid tissue, eventually leading to goiter.

Dr Ahmed Esawy

Dr Ahmed Esawy

Goiterogenesis

Iodine deficiency results in hypothyroidism

Increasing TSH causes hypertrophy of thyroid (diffuse

nontoxic goiter)

Follicles may become autonomous; certain follicles will

have greater intrinsic growth and functional capability

(mult inodular goiter)

Follicles continue to grow and function despite

decreasing TSH (toxic mul tinodular goiter)

Sporadic vs. endemic goiter

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Simple (Colloid) Goiter

Diffuse goiter

Usually euthyroid

Peaks in puberty

Endemic goiter

Compensatory TSH

Follicular cell hypertrophy and

hyperplasia

Goiterogens (eg, cassava)

Non endemic or sporadic less

common

Rare hereditary defects in thyroid

hormone synthesis

Note distension of follicles with colloid

and flattening of epithelial cells

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Multinodular Goiter

Most simple goiters become transformed into

multinodular goiters.

Nontoxic or toxic (induce thyrotoxicosis)

No ophthalmopathy or dermopathy

May cause cosmetic disfigurement and tracheal

compression

May induce the superior vena caval syndrome

Differentiation of a dominant nodule from a thyroid

tumour may be difficult.

Retrosternal extension

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3-Differential diagnosis

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GIOTRE

DIFFUSE FOCAL/NODULAR

MULTINODULAR UNINODULAR

NON-TOXIC TOXIC

Structural / Anatomy

Functional /biochemical

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DIFFUSE GIOTRE •the whole thyroid appearing to be enlarged Size

hyperthyriodism Graves disease Suppurative thyroiditis Drug-induced thyroiditis Riedel s thyroiditis Iodine deficiency Organification defect pregnant ,menopause thyroiditis Silent thyrioditis

hypothyriodism Hshimoto s thyroiditis Iodine deficiency Radiation exposure Subacute thyroiditis post partum thyroiditis

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GIOTRE

DIFFUSE FOCAL/NODULAR

MULTINODULAR

UNINODULAR

HYPERTHYRIODISM thyrotoxic giotre

HYPOTHYRIODISM Hypothyriod giotre

Euthyroid goiter: - Diffuse goiter – U/S - MNG – U/S, FNA for dominant nodule Dr Ahmed Esawy

NODULAR GIOTRE

BENIGN ADENOMA NEOPLASM COLLIOD

Cyst Complex cyst

Focal thyrioditis

MALIGNANT

As function: biochemical - hot (toxic) - cold (N :TSH) cold nodule in a toxic thyroid (as may occur in Grave’s disease) Dr Ahmed Esawy

Nontoxic Goiter

Simple, Colloid, or Multinodular Enlargement of entire gland without

producing nodularity and without evidence of functional disturbance (euthyroid)

Causes Lack of Iodine

Compensatory increase of TSH = follicular cell hypertrophy

Sporadic Goiter Diffuse, Uninodular, or multinodular

Ingestion of Substances, hereditary enzyme defects

Simple Goiters may evolve = Multinodular Goiters Calcification, Degeneration, Fibrosis,

and Hemorrhage

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BENIGN NODULAR GIOTRE Non toxic

NEOPLASM Benign thyroid cysts (degenerated nodules) Simple cyst Haemorrhagic Cystic nodule in solid tumour

COLLIOD Dominent colliod nodule in MNG uninodular

Adenoma

macrofollicular (simple colliod) microfollicular (fetal) embryonal (trabecular) hurthe cell adenoma atypical adenoma adenoma with papillae signet ring adenoma

Inflammatory disorder subacute thyrioditis lymphocystic thyrioditis granulomatous disease (sarciodosis/TB) abscess

developmental dermiod unilateral lobe agenesis

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MALIGNANT NODULAR GIOTRE

MALIGNANT Papillary carcinoma Follicular carcinoma

Hurthle cell tumor Medullary Thyroid Carcinoma Anaplastic Carcinoma Lymphoma of thyroid

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NODULAR GIOTRE

UNINODULAR

MULTINODULAR MNG

INACTIVE

COLD

TOXIC NODULE

TOXIC NODULE

TOXIC MULTINODULAR GIOTRE INACTIVE

COLD

MALIGNANT BENIGN Dr Ahmed Esawy

Cold Thyroid Nodule BENIGN TUMOR

Nonfunctioning adenoma Cyst (20%) Involutional nodule Parathyroid tumor

INFLAMMATORY MASS Focal thyroiditis Granuloma Abscess

MALIGNANT TUMOR Carcinoma Lymphoma Metastasis

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“Cold” nodule = focal defect

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Cold nodule, R lobe (99mTcO4)

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Cystic Areas in Thyroid 25% of all thyroid nodules!

Anechoic fluid + smooth regular wall: Colloid accumulation in goiter = colloid-filled dilated macrofollicle Simple cyst (extremely uncommon)

Solid particles + irregular outline: Hemorrhagic colloid nodule Hemorrhagic adenoma (30%) Necrotic papillary cancer (15%) Liquefaction necrosis in adenoma / goiter Abscess Cystic parathyroid tumor

bloody fluid = benign / malignant lesion

clear amber fluid = benign lesion

Cystic lesions often yield insufficient numbers of cells!

Dr Ahmed Esawy

HYPOTHYRIODISM

CONGENITAL Hypoplasia & mal-descent Agenesis ,hemiagenesis Ectopia thyriod (sublingual thyriod) Familial enzyme defects Iodine deficiency (endemic cretinism) Intake of goitrogens during pregnancy Pituitary defects Idiopathic

Iodine deficiency(diffuse giotre) Hashimoto´s thyroiditis (autoimmune thyroiditis) Subacute (De Quervein’s) thyroiditis

Thyroidectomy or RAI therapy TSH or TRH deficiency Medications (iodide & Cobalt,amiodarone)) Idiopathic Post partum amyliodosis

ACQUIRED

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INCREASE THYRIOD HORMONE

Thyrotoxicosis refers to the manifestation of excessive quantities of circulating thyroid hormone

Hyperthyroidism refers only to the subset of thyrotoxic diseases caused by the overproduction of the thyroid hormone by the gland itself.

Dr Ahmed Esawy

HYPERTHYROIDISM

ETIOLOGY

• Graves’ disease ( autoimmune ).

• Toxic multi-nodular goiter ( toxic MNG ).

• Toxic nodule (hot or warm nodule)

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COMMON CAUSES OF HYPERTHYROIDISM

autoimmune diseases Graves disease (the most common cause of hyperthyroidism Lymphocytic thyroiditis With hyperthyroidism (silent thyroiditis) Postpartum thyrotoxicosis (PPT)

functioning thyroid adenomas (Hyperfunctioning thyroid

nodules (toxic adenoma, toxic multinodular goiter, Plummer's disease)

Toxic multinodular goiter

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High blood levels of thyroid hormones (hyperthyroxinemia)

Inflammation of the thyroid (thyroiditis). (subacute thyrioditis) (DeQuervain's) and Hashimoto's thyroiditis (Hypothyroidism immune-

mediated), These may be initially associated with secretion of excess thyroid hormone, but

usually progress to gland dysfunction and, thus, to hormone deficiency and hypothyroidism.

Oral consumption of excess thyroid hormone tablets

Amiodarone, an antiarrhythmic drug,

Postpartum thyroiditis (PPT)

A struma ovarii is a rare form of monodermal teratoma that contains mostly thyroid tissue

Excess iodine consumption notably from algae such as kelp.

Hypersecretion of thyroid stimulating hormone (TSH), which in turn is almost always caused by a pituitary adenoma

Thyroid tumor. A noncancerous thyroid tumor may make and secrete increased amounts of thyroid hormones.

LESS COMMON CAUSES OF THYROTOXICOSIS HYPERTHYROIDISM

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Varieties of Thyrotoxicosis

Associated with thyroid hyperfunction:

Excess production of TSH(rare)

Abnormal thyroid stimulator-Eg:Graves’ disease

Intrinsic thyroid autonomy-Eg:Hyperfunctioning adenoma, Toxic multinodular goitre

Not associated with thyroid hyperfunction:

Disorders of hormone storage-Eg:Subacute thyroiditis, chronic thyroiditis

Extrathyroid source of hormone- Thyrotoxicosis factitia,ectopic thyroid tissue- struma ovarii, functioning follicular Ca.

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DEVELOPMENTAL ABNORMALITIES OF

THYROID GLAND

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developmental process of the thyroid gland during the embryonic period. Descent of the thyroid gland during embryological development can be visualized from the thyroglossal duct cyst or remnant/ectopic tissue to its ultimate position, in the pretracheal region Dr Ahmed Esawy

Hemiagenesis of the thyroid gland. Axial contrast-enhanced CT scan demonstrates absence of the left lobe, which is a typical finding in hemiagenesis.

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Right lobe is enlarged, with mixed echogenic mass (arrows). Fine-needle aspiration was consistent with adenoma.

Thyroid Hemiagenesis with Adenoma

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CT scan obtained 9 months before sonogram shows absent left thryoid lobe and enlarged right thryoid lobe with small low-attenuation lesion (arrows).

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A 44-yearold woman with midline thyroid remnant tissue. Contrast-

enhanced CT image (a) shows a small, strongly enhanced mass between the strap muscles at the anterior aperture of the thyroid cartilage (arrows). The thyroid gland has a normal appearance in the lower neck (b).

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a–d. A 39-year-old woman with midline thyroid remnant tissue. T1- (a) and T2-weighted (b) MR images show a superficial lesion with intermediate signal intensity in the right paramedian region, at the anterior aperture of the thyroid cartilage (arrows). Contrast-enhanced T1-weighted MR images (c, d) show strong homogeneous enhancement of the mass (c, arrows). This lesion has the same signal intensity and enhancement pattern as the thyroid gland in all sequences. Dr Ahmed Esawy

a–c. A 35-year-old man with midline ectopic thyroid tissue. Contrastenhanced CT image (a) shows round, enhanced ectopic thyroid tissue at the anterior aperture of the thyroid cartilage (arrows). The thyroid gland is located in the normal location; however, agenesis of the isthmus with hypoplastic thyroid lobes exists (b, asterisk). An image of the I-131 scan (c) illustrates a well-defined area of uptake nearly at the hyoid bone, located at the midline (arrows).

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a, b. A 42-year-old man with lateral ectopic thyroid tissue. Contrast-enhanced CT images (a, b) show ectopic thyroid tissue in the submandibular and parapharyngeal regions at the hyoid bone level. The left submandibular gland is pushed anterolaterally by the ectopic tissue (a, arrows). The right thyroid lobe is visualized in the normal location and incidentally detected as a hypodense nodule in the right lobe. Agenesis of the isthmus and left thyroid lobe is noted (b).

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A 59-year-old man with lateral ectopic thyroid tissue. Contrast-enhanced CT image series show a homogeneous, dumbbell-shaped mass with uniform enhancement that extends into the submandibular region from the left thyroid lobe region. No isthmus is present

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Lingual thyroid

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34-year-old man with a thyroglossal duct cyst. Contrast-enhanced CT image shows a cystic mass in the anterior midline of the neck, at the level of the thyroid cartilage (arrows). The cyst contains thin septations. Histopathological examination revealed a thyroglossal duct cyst.

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Thyroglossal duct cyst. A cystic left mass (asterisk) embedded within the paralaryngeal strap muscles on T1-weighted MR image. The fluid is mildly hyperintense; the subcutaneous fat is normal.

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Thyroglossal duct cyst. Enhanced CT (A) shows a hypodense left neck lesion (asterisk) located within the paralaryngeal strap muscles (m). This appearance resembles a "snake swallowing an egg" (B). Thyroglossal duct cyst (asterisk), strap muscles (m). Dr Ahmed Esawy

Thyroglossal duct cyst. Enhanced CT at level of hyoid bone (A) shows a lateral cystic lesion (asterisk) notching the inner surface of the hyoid (arrow). Inferiorly at the level of the pyriform sinuses (B), the lesion (asterisk) is embedded in the paralaryngeal strap muscles (m).

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Thyroglossal duct cyst. Enhanced CT at level of hyoid bone shows a lateral cystic lesion (asterisk) notching the inner surface of the hyoid (arrow). Inferiorly at the level of the pyriform sinuses (B), the lesion (asterisk) is embedded in the paralaryngeal strap muscles (m).

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Thyroglossal duct cyst. T1-weighted MR image demonstrating a mildly hyperintense midline lesion (arrow) notching the dorsal surface of the hyoid bone (arrowheads).

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a–d. A 48-year-old woman with a giant thyroglossal duct cyst. Axial T1-weighted MR image (a) shows a well-defined cystic mass in the floor of the mouth at the tongue base, the classic location for a thyroglossal duct cyst. The increased signal intensity of the cyst is due to either proteinaceous content or a prior hemorrhage (a, arrows). Coronal T2-weighted MR image (b) reveals high hyperintensity of the cyst, with mural thickening (arrows).

The axial (c) and sagittal (d) contrast-enhanced T1-weighted MR images with fat suppression show mild rim enhancement of the cyst with strong enhancement of the thickened wall due to residual thyroid tissue (arrows).

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Pyramidal lobe. Axial contrast-enhanced CT scan shows persistence of the distal portion of the thyroglossal duct. This condition is present in 50% of the population. P = pyramidal lobe.

Dr Ahmed Esawy